1. Field of the Invention
The present invention relates to a device for treating water in a basin.
More specifically, but not exclusively, the invention is advantageously used in different types of basins, such as, for example, tanks for aquiculture, fish-farming basins, aeration tanks of water purification plants, lakes undergoing reclamation, etc. The device in question may be used in particular for aerating and/or oxygenating the water, but it may also serve for other types of water treatment, such as, for example, stirring, degassing, destratification, de-icing, remixing, etc.
2. Description of the Prior Art
Various types of apparatus which perform the abovementioned tasks are already known; some of these are illustrated, for example, in the following patent publications: DE 3,417,039, EP 0,088,850, U.S. Pat. No. 4,157,304, U.S. Pat. No. 4,409,107, U.S. Pat. No. 4,514,343, U.S. Pat. No. 4,732,682, U.S. Pat. No. 4,741,825, U.S. Pat. No. 4,882,099, U.S. Pat. No. 4,954,295 and U.S. Pat. No. 5,118,450.
In particular the present invention refers to a device provided with an operating group immersed in the water and comprising a decompression chamber, a rotating propeller and a motor for driving the propeller. The decompression chamber has an inlet communicating with a suction duct which emerges above the free surface of the water, and an outlet immersed in the water; the propeller is situated outside the decompression chamber in the vicinity of the outlet. During use, operation of the propeller empties the decompression chamber of the water and causes, via the suction duct, sucking-in of air which is mixed with the water in the basin.
A device of this type is already known from the European publication EP 0,562,314 which illustrates a floating structure made of plastic material and comprising two parallel, hollow, floating cables underneath which the operating group is located. This device has, however, certain drawbacks.
Firstly, in the case where the level of the water inside the basin falls, the operating group may touch the bottom, with the consequent incorrect operation or breakdown of the device.
Secondly, when the device is outside the water--for example so that operations such as storage, transportation, checking, maintenance, etc., may be performed--the motor is exposed to accidental knocks with the risk of damage.